Integrated Porcelain System for a Dental Prosthesis

ABSTRACT

An integrated dental porcelain system for making dental prostheses and restorations is provided. The system includes three universal major components: a) opaque porcelain composition; b) pressable dentin ingot; and c) veneering porcelain composition that can be used interchangeably for making restorations. Techniques for making the prostheses and restorations include porcelain fused-to-metal (PFM), press-to-metal (PTM), and either pressed and/or machined all-ceramic methods. The system uses both a hand-layering of veneering porcelain (PFM technique) and a hot-pressing process (PTM and all-ceramic technique) to fabricate the prostheses and restorations.

CLAIM OF PRIORITY

This application is a Continuation of U.S. patent application Ser. No.12/156,169, filed on May 30, 2008, which is herein incorporated byreference for all purposes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to materials for making dentalprostheses and restorations such as inlays, onlays, veneers, crowns, andbridges. Particularly, the materials include one universal opaque, oneuniversal pressable ingot, and one universal veneering porcelain thatcan be used interchangeably to manufacture a prosthesis or restorationusing different techniques. This includes porcelain-fused-to-metal(PFM), press-to-metal (PTM), and pressed or computer-aided-manufacturing(CAM) machined all-ceramic techniques.

2. Brief Description of the Related Art

There are various methods known in the dental arts for making dentalprostheses and restorations. By the term, “prosthesis” or “restoration”as used herein, it is meant any product that replaces or restores losttooth structure, teeth, or oral tissue including, but not limited to,implant stents, bite registrations, crown and bridges, fillings,baseplates, splints, denture liners, custom trays, artificial teeth,repairs for natural teeth, veneers, denture repairs, denture relines,retainers, orthodontic components, provisional dental devices, inlays,onlays, orthodontic appliances, temporary dentures, temporary partialdentures, maxillofacial prostheses, obturators, and occular prostheses,and the like.

Conventional dental prostheses may include a metal coping orsubstructure to provide additional mechanical strength and durability tothe prosthesis. In practice, the metal copings are covered with glass orceramic-based materials that mimic the color and form of natural teeth.The metal copings support the glass or ceramic-based veneering layer andprovide enhanced structural strength and toughness to the restoration.

A traditional method for making a dental prosthesis is known as“porcelain-fused-to-metal” (PFM). Typically, the process of making a PFMrestoration involves applying three layers of porcelain onto a metalframework. Initially, an opaque porcelain composition, in either powderor paste form, is applied over a metal framework to form an opaque layerthat masks the metal. Subsequently, a dentin body layer is built upusing dentin porcelain powder and then a third layer simulating theincisal portion of a natural tooth is built up using enamel porcelainpowder. In PFM restorations, the layering of the wet porcelaincompositions is traditionally done by hand. The porcelain compositionsare fired at high temperatures to form hard and durable dentin andincisal layers having the appearance of natural teeth. Other porcelainmaterials, such as opaceous dentin, dentin modifier, and stainporcelain, margin, and final margin porcelains can be added to enhancethe esthetics of the final dental restoration. The PFM restorations canbe finished by applying a thin layer of glaze porcelain to provide aglossy surface finish.

One drawback with PFM restorations is that the dark-colored margin maybe exposed at the gum line and the restoration may not have the mostpleasing esthetics. To improve esthetics, “all-ceramic” systems havebeen developed. These all-ceramic systems use a ceramic core in place ofthe metal framework. The ceramic core is coated with at least oneporcelain layer. In one technique, an all-ceramic prosthesis having acore is fabricated using a hot-pressing technique. (For example, theEmpress™ prosthetic system (Ivoclar Vivadent AG, Liechtenstein) wasdeveloped.) An alternative way of fabricating all-ceramic cores is touse a computer-aided-manufacturing (CAM) method and machine directly ona ceramic block as described in the Cerec™ system (Sirona Dental SystemsGmbH, Germany). While all-ceramic prostheses may offer improvedesthetics over PFM restorations, the all-ceramic prostheses tend to bemore brittle. Traditionally, all-ceramic prostheses have been limitedgenerally to anterior up to pre-molar applications. Although in recentyears, using high strength alumina and zirconia as the core has allowedall-ceramic restorations to be used in posterior and bridgeapplications.

Another method that has grown in popularity over the last several yearsis known as the “press-to-metal” (PTM) process. The PTM process involvesplacing a metal coping or substructure in a mold. The coping is thencoated with an opaque porcelain composition which may be in powder orpaste form. The opaque coating is followed by wax-up and spruing to formthe prosthesis form. The form is then invested in a ceramic investmentmaterial, and the wax is burned out. This forms the prosthesis mold. Aporcelain layer is fused to the opaque surface by hot-pressing an ingotporcelain material onto the coping contained in the mold at fusingtemperatures. The hot-pressed porcelain flows into the burn-out cavityto form the dentin layer. The prosthesis is then divested of the moldingmaterial and finished. The result is a strong and tough dentalprosthesis having a metal substructure that is veneered with porcelain.The prosthesis has generally good esthetics with integrated transparencythat matches the appearance of natural dentition.

Conventional methods for making PFM, PTM, and all-ceramic restorationsare described in the patent literature. For example, Kosmos, U.S. Pat.No. 4,741,699 discloses making a porcelain dental restoration havingfluorescence that matches the fluorescence of natural teeth. Therestoration includes a metal supporting substrate, a body layer, andincisal layer. An aqueous slurry of an opaque porcelain is applied andfired to the metal substrate. A body layer and incisal layer are formedfrom porcelain powder mixtures containing fluorescent pigment. Thepowder mixtures comprise a base porcelain, stained porcelain, andfluorescing agent and are applied by hand to build-up the restoration.

Komma et al., U.S. Pat. No. 5,281,563 describes methods for making metaland ceramic dentures. The ceramic powder is applied to the metallicframework as an aqueous slurry and fired at elevated temperatures toproduce the prosthesis. Komma notes that it is important that the firingtemperature (processing temperature) of the ceramic body be at least100° C. below the solidus temperature of the material in the metallicframework and the coefficient of thermal expansion of the ceramic bodybe only very slightly less than that of the metallic material, so thatno cracks are produced in the lining layer during firing and coolingdown.

Brodkin et al., U.S. Pat. No. 6,428,614 is directed to an opaqueporcelain material for making both all-ceramic andporcelain-fused-to-metal (PFM) restorations. The opaque porcelainexhibits a coefficient of thermal expansion (CTE) substantially equal toor slightly above the CTE of the metal to which the porcelain is beingapplied. The porcelain material is fabricated from a mixture of two fitcompositions. The porcelain material has a composition of 48 to 65%SiO₂; 10 to 15% Al₂O₃; 0.5 to 2% CaO; 1.5 to 3% Li₂O; 15 to 17% K₂O; 4to about 6% Na₂O; and 0.4 to 1% F.

Chu and Banasiak, US Patent Application Publication No. US 2007/0196788discloses a dental prosthesis having a metal coping that is coated withan opaque coating. A single porcelain layer having an integratedtooth-like translucency is coated over the opaque coating. The porcelainlayer is formed of a dentin frit and enamel frit that is sintered intoan ingot shape. The weight percent of dentin frit is in the range of 70to 85% and the weight percent of enamel frit is in the range of 15 to30%. The resulting restoration has strong substructure that is veneeredwith porcelain having an integrated transparency.

One major problem with conventional PFM, PTM, and all-ceramic systemsavailable in the marketplace today is that the components of each systemare tailored to their own applications. The materials cannot be usedinterchangeably across the systems due to the thermal incompatibilityamong the components and/or metal substructure. Hence, systems withvarious components need to be purchased separately for making differenttypes of restorations. This may cause over-inventory problems andconfusion over mixing use of the components in dental laboratories.

It is an object of the present invention to provide an integratedporcelain system having components that can be used interchangeablyamong porcelain-fused-to metal (PFM), press-to-metal (PTM), and pressedor computer-aided-manufacturing (CAM) machined all-ceramic restorationsIt is another object of the invention to provide a universal opaqueporcelain composition that can be used for making PFM and PTMprostheses. Yet another object of the invention is to provide universalpressable ingots that can be used for making dentin body layers overopaqued metal framework in PTM prostheses and all-ceramic cores. It isstill another object of the invention to provide a universal veneeringporcelain composition that can be used for making dentin-enamel layersand enamel layers. These and other objects, features, and advantages ofthe present invention are evident from the following description andillustrated embodiments.

SUMMARY OF THE INVENTION

The present invention provides an integrated dental porcelain system formaking dental prostheses and restorations. The system includes threeuniversal major components: a) opaque porcelain composition; b)pressable dentin ingot; and c) veneering porcelain composition that canbe used interchangeably for making porcelain fused-to-metal (PFM),press-to-metal (PTM), and either pressed and/or machined all-ceramicrestorations. The system uses both a hand-layering of veneeringporcelain (PFM) and a hot-pressing process (PTM & all-ceramic) tofabricate a prosthesis or restoration for the patient.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features that are characteristic of the present invention areset forth in the appended claims. However, the preferred embodiments ofthe invention, together with further objects and attendant advantages,are best understood by reference to the following detailed descriptionin connection with the accompanying drawings in which:

FIG. 1 is a cross-sectional schematic view of a PFM crown on a die modelfabricated with components in accordance with the invention;

FIG. 2 is a cross-sectional schematic view of a full-contour PTM crownon a die model fabricated with components in accordance with theinvention;

FIG. 3 is a cross-sectional schematic view of an incisal cutback PTMcrown on a die model fabricated with components in accordance with theinvention;

FIG. 4 is a cross-sectional schematic view of a full-contour, pressedall-ceramic crown on a die model fabricated with components inaccordance with the invention;

FIG. 5 is a cross-sectional schematic view of an incisal cutback,pressed all-ceramic crown on a die model fabricated with components inaccordance with the invention;

FIG. 6 is a cross-sectional schematic view of a full-contour,CAM-machined all-ceramic crown on a die model fabricated with componentsin accordance with the invention; and

FIG. 7 is a cross-sectional schematic view of an incisal build-up,CAM-machined all-ceramic crown on a die model fabricated with componentsin accordance with the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to materials, methods, and kits for makingdental prostheses. The materials of this invention which may be suppliedas components of a kit, can be used to provide porcelain/metalrestorations, using either hand layering of veneering porcelain (PFM) ora pressing process (PTM) to apply a finished surface, along withall-ceramic restorations.

The materials for making the dental prostheses in accordance with thisinvention include principally: (1) universal opaquing porcelains, ineither powder or paste form, for masking the surface of metal frameworkthat would otherwise be visible through the porcelain veneer. This isused for making both PFM and PTM restorations; (2) universal pressableingots for pressing dentin body over opaqued metal framework to make PTMrestorations or for pressing a stand-alone all-ceramic core; and (3)universal dentin/enamel porcelain for building incisal layer in makingeither PFM, PTM, and/or all-ceramic (either pressed or machined)restorations. These materials can be supplied in a kit to a dentallaboratory for making the dental prostheses.

In addition, the kit may include a shade stain porcelain paired with aglaze porcelain for shading and finishing either full-contour PTM and/orall-ceramic restorations. The applied shade stain and glaze porcelaincompositions are fired in a single step. Also, the same glaze porcelaincan be used for finishing PFM, incisal cutback PTM, and all-ceramicrestorations in accordance with this invention. Further, the kit mayinclude other porcelain materials such as opaceous dentin, dentinmodifier, correction, margin, and final margin porcelain for finishingthe prosthesis, as necessary. The different components of the kit arediscussed in further detail below.

Universal Opaque Porcelain

The universal opaque porcelain composition is used for coating the metalsubstructure of the prosthesis. The opaque coating masks the metalsubstructure and prevents the dark-colored surface and edges of thesubstructure from being visible. This coating step results in an“opaqued” metal substructure. The opaque porcelain can be applied overthe metal substructure in powder or paste form. The opaque porcelain canbe applied by spraying, slurry dip, electro-depositing, or other methodsknown to those skilled in the art. Then, the composition is fired toform a hard and durable coating. The firing temperature of the opaqueporcelain is preferably between 800° C. and 1000° C., more preferablybetween 830° C. and 930° C., and most preferably between 860° C. and900° C.

The opaque coating, which forms as a result of this firing step, hasthermal compatibility and thermal stability with a later appliedporcelain veneer layer. By the term, “thermal compatibility” or“thermally compatible” with respect to the opaque coating, it is meantthat no substantial cracks are visible in the coating after firing at atemperature between 800° C. and 1000° C. upon examining the coatingunder an optical microscope (10X magnification); and no substantialcracks, are visible in the porcelain veneer layer after firing at atemperature between 700° C. and 1000° C. upon examining the layer underan optical microscope (10× magnification). The thermal compatibilitybetween the opaque coating and porcelain veneer layer of this inventionis due to several reasons including the chemical composition ofmaterials and similar coefficient of thermal expansion (CTE) values. Ingeneral, the CTE of the opaque coating is approximately equal to orslightly lower than that of the metal substructure and is approximatelyequal to or slightly greater than that of the veneering porcelain.

By the term, “thermal stability” or “thermally stable” with respect tothe opaque coating, it is meant that the opaque coating retains itsshape and form and remains adhered to the metal substructure aftermultiple firings (that is, at least two and up to five firings) of thesubsequently applied porcelain veneer layer at a temperature between700° C. and 1000° C. The thermal stability of the opaque coating can bedetermined by examining the restoration coated with the opaque coatingand porcelain veneer layer under optical microscope (10× magnification).If the opaque coating has drifted or migrated away from the metalsubstructure, the opaque coating is not considered to be thermallystable with the porcelain veneer layer. The porcelain veneer layer canbe applied to the opaque coating by hot-pressing or manual hand-layeringas described further below.

A preferred opaque porcelain composition is described in the followingTable 1.

TABLE 1 CHEMICAL COMPOSITION OF OPAQUE WHITE PORCELAIN PASTE OxideConcentration Range (Wt. %) SiO₂ 42-46%  Al₂O₃ 8-12%  Na₂O 2-5% K₂O 6-9%Li₂O 0-2% CaO 0-2% MgO 0-2% ZrO₂ 20-30%  SnO₂ 1-4% Tb₄O₇ 0-2% CeO₂ 0-3%TiO₂ 0-2% Sb₂O₃ 0-0.1%  Fluorescing Agent 0-5% Total 100% 

The materials of this invention, including the opaque porcelaincomposition, can be used with various metal copings and substructures.In general, metals and alloys and their mixtures, such as nobel alloys,palladium-based alloys, cobalt-based alloys, nickel-based alloys, puretitanium and alloys, gold-based metal-ceramic alloys, nickel chromiumalloys, and the like can be used as copings and substructures. Moreparticularly, two commercially-available alloys suitable for use arenon-precious “DeguDent U” and high-noble “UltraCrown SF”, both marketedby Dentsply International. These alloys can be used to make a frameworkby conventional casting techniques known to those skilled in the dentalarts. The materials of this invention are particularly suitable for usedwith conventional PFM alloys, for example, having coefficients ofthermal expansion (CTE) of about 14.0 ppm/C° at 500° C.

Universal Pressable Ingots

The universal pressable ingots are used to form a dentin body layer overthe opaqued metal framework in Press-to-Metal (PTM) protheses orstand-alone, all-ceramic cores using a hot-pressing technique. Anappropriate amount of dentin body ingots, in either 2 gram or 5 gramsize, is pressed into the prostheses mold. The shade of the dentin bodyingots is selected so that the resulting layer will matches the naturalcolor of the dentin in the patient's teeth. The pressing temperature ispreferably between 700° C. and 1000° C., and more preferably between840° C. and 940° C., and most preferably between 870° C. and 910° C. Thetypical pressing conditions are as follows: 700° C. (low temperature);890° C. (high temperature); 60° C. per minute (heat rate); 20 minutes(time at high temperature); 10 to 30 minutes (pressing time) and 2.5 to4.25 bars (pressing time). The prosthesis is then divested of themolding material for subsequent veneering porcelain application asdiscussed further below.

After the ingot has been pressed at a temperature in the range of 870°C. to 910° C., the pressed ingot material forms a dentin body layer thatis thermally compatible with the other porcelain layers, that is, theopaque coating, and the subsequently applied veneering, and stainlayers. The dentin body layer is also thermally stable when theveneering and stain layers are subsequently applied and fired.

By the term, “thermal, compatibility” or “thermally compatible” withrespect to the dentin body layer, it is meant that no substantial cracksare visible in the dentin body layer after the layer has been pressed ata temperature between 870° C. and 910° C. upon examining the pressedlayer under an optical microscope (10× magnification); and nosubstantial cracks, are visible in the porcelain veneer layer afterfiring at a temperature between 810° C. and 860° C. upon examining thelayer under an optical microscope (10× magnification).

By the term, “thermal stability” or “thermally stable” with respect tothe dentin body layer, it is meant that the dentin body layer retainsits shape and form and remains adhered to the opaqued metal substructureafter multiple firings (that is, at least two and up to five firings) ofthe subsequently applied porcelain veneering layer at a temperaturebetween 810° C. and 860° C.

A preferred ingot porcelain composition that can be used in accordancewith this invention is described in the following Table 2

TABLE 2 CHEMICAL COMPOSITION OF INGOT PORCELAIN COMPOSITION FOR MAKINGDENTIN BODY LAYER Oxide Concentration Range (Wt. %) SiO₂ 63-66%  Al₂O₃10-14%  Na₂O 3-7% K₂O 9-12%  Li₂O 0-2% CaO 1-4% BaO 0-3% Tb₄O₇ 0-2% CeO₂0-2% Total 100% 

Universal Veneering Porcelain

The universal veneering porcelain composition is used to form a veneerlayer over the opaqued metal substructure or all ceramic core. Theveneering porcelain composition is applied to the dental prosthesis toform a dentin-enamel layer (PFM applications where a dentin body layerhas not been formed previously) or enamel layer (PTM and all-ceramicapplications where a dentin body layer has been formed previously.)After the composition has been fired to a temperature in the range of800° to 850° C., the coating forms a hard and durable layer having ashade that matches the shade and translucency of the patient's naturalteeth. The resulting layer is thermally compatible and thermally stablewith the opaqued metal substructure and all-ceramic core.

By the term, “thermal compatibility” or “thermally compatible” withrespect to the veneering porcelain dentin-enamel or enamel layer, it ismeant that no substantial cracks are visible in the dentin-enamel orenamel layer after the layer has been fired at a temperature between810° C. and 860° C. upon examining the fired layer under an opticalmicroscope at 10× magnification; and no substantial cracks, are visiblein the dentin body layer after pressing at a temperature between 870° C.and 910° C. upon examining the layer under an optical microscope at 10×magnification.

By the term, “thermal stability” or “thermally stable” with respect tothe veneering porcelain dentin-enamel or enamel layer, it is meant thatthe dentin-enamel or enamel layer retains its shape and form and remainsadhered to either the opaqued metal substructure or dentin body layerafter firing the subsequently applied shade stain and glaze overlayer ata temperature between 780° C. and 840° C.

A preferred veneering porcelain composition is described in thefollowing Table 3.

TABLE 3 CHEMICAL COMPOSITION OF INGOT VENEERING PORCELAIN FOR MAKINGDENTIN-ENAMEL OR ENAMEL LAYERS Oxide Concentration Range (Wt. %) SiO₂62-65%  Al₂O₃ 8-11%  Na₂O 8-11%  K₂O 4-7% Li₂O 0-2% CaO 2-5% BaO 0-3%MgO 1-4% SnO₂ 0-2% Tb₄O₇ 0-2% CeO₂ 0-2% Sb₂O₃ 0-2% P₂O₅ 0-0.1%  TiO₂0-0.1%  F 0-1% Total 100% 

In addition, a one-step fired shade stain material paired with a glazeporcelain material can be applied over PTM and/or all-ceramicfull-contour crowns and bridges made with full-contour technique tocomplete the restoration. The shade stain porcelain composition providesthe restoration with the proper color shade so that the restorationmatches the color shade of neighboring teeth. Meanwhile, the glazeporcelain provides the restoration with a hard and smooth film coating.The finished restoration has a shiny and glossy appearance after theshade stain and glaze materials have been applied. The shade stain andglaze are separate and distinct materials, but they are normally appliedtogether and are collectively and singularly referred to herein asforming an overlayer. Once the shade stain and porcelain materials areapplied, they are fired in a single step. The firing temperature of theshade stain and glaze overlayer is preferably between 750° C. and 950°C., more preferably between 800° C. and 900° C., and most preferablybetween 780° C. and 840° C. It is also recognized that, the same glazeporcelain can be applied over PFM, incisal cutback PTM and/orall-ceramic cores to complete these restorations. In the case of PFM,incisal cutback PTM and/or all-ceramic cores, it is not necessary toapply the shade stain porcelain material, because these products arealready shaded. Additional shade stain does not need to be applied tothese restorations. The components used to make the shade stain andglaze porcelain materials are listed generally in the following Table 4.It should be understood that the shade stain composition will differfrom the glaze porcelain composition in view of the different oxidesand/or weight percentage of ingredients used in the respectivecompositions.

TABLE 4 COMPONENTS USED IN SHADE STAIN AND GLAZE PORCELAIN MATERIALSOxide Concentration Range (Wt. %) SiO₂ 56-64%  Al₂O₃ 6-13%  Na₂O 7-15% K₂O 7-15%  Li₂O 0-5% CaO 0-3% MgO 2-5% SnO₂ 0-4% Tb₄O₇ 0-3% CeO₂ 0-2%B₂O₃ 0-5% Sb₂O₃ 0-0.5%  F 0-2.5%  TiO₂ 0-1% Total 100% 

Referring now to the Figures, the dental prostheses made in accordancewith this invention are shown in detail. FIG. 1 shows a crown (8) madeby a porcelain fused-to-metal (PFM) process is shown positioned on a diemodel (10). The crown includes a metal coping or substructure (12) whichis coated with a universal opaquing porcelain layer (14), universaldentin veneering porcelain layer (16), universal enamel veneeringporcelain layer (18), and overglaze porcelain layer (20).

FIG. 2 shows a PTM crown (8) made using a full-contour technique on adie model (10). The crown (8) has a metal coping (12) with a universalopaquing porcelain (14), universal pressable ingot that forms a dentinbody layer (22), and a shade stain/glaze porcelain (24).

FIG. 3 shows a PTM crown (8) made using an incisal cutback technique ona die model 10. The crown (8) has a metal coping (12) with a universalopaquing porcelain (14), universal pressable ingot that forms a dentinbody layer (22), universal enamel veneering porcelain (18), andoverglaze porcelain (20).

FIG. 4 shows an all-ceramic crown (8) made using a full-contourtechnique on a die model (10). The crown (8) has an all-ceramic copingpressed using a universal pressable ingot that forms a dentin body layer(22), and shade stain/glaze porcelain (24).

FIG. 5 shows an all-ceramic crown (8) made using an incisal cutbacktechnique on a die model (10). The crown (8) has an all-ceramic copingpressed using a universal pressable ingot that forms a dentin body layer(22); a universal enamel veneering porcelain that forms an enamel layer(18); and overglaze porcelain (20).

FIG. 6 shows an all-ceramic crown (8) made using a machinable block on adie model (10). The crown (8) has an all-ceramic full-contour copingmachined using machinable block (26) with a shade stain/glaze porcelain24.

FIG. 7 shows an all-ceramic crown (8) made using machinable block on adie model (10). The crown (8) has an all-ceramic coping machined usingmachinable block (26); a universal enamel veneering porcelain that formsan enamel layer (18); and overglaze porcelain (20).

The finished restoration made in accordance with this invention can besubjected to a “thermal shock” test to further evaluate its thermalproperties. In this test, the finished restoration is heated to a giventemperature in a furnace. After the restoration has been removed, it isquenched into iced water (normally having a temperature between 0° C.and 5° C.). Then, the restoration is examined under an opticalmicroscope (10× magnification) to determine if any cracks have formed inthe restoration. For example, the restoration can heated to 80° C. inthe furnace, removed, and quenched in cool water. If no cracks arevisible upon microscopic examination, the restoration is placed back inthe furnace and heated to a higher temperature. Normally, thetemperature is incrementally increased by ten degrees (10° C.). Thus,the restoration is heated to 90° C. in the furnace, removed, andquenched in cool water. The restoration is microscopically examined forcracks. This sequence of heating and quenching is repeated until thecritical quenching temperature (temperature at which cracks firstappear) is determined. Preferably, both single unit crowns andthree-unit bridges made in accordance with this invention have acritical quenching temperature of about 110° C.

Physical/Mechanical Properties

The physical/mechanical properties of the integrated dental porcelainsystem of this invention are described in the following Table 5. Thecomponents were tested for different properties according to the methodsdescribed in ISO 6872 (1995-09-01) for dental porcelains and ISO 9693(1999) for metal-ceramic dental restorative systems. The components meetall ISO requirements as shown in Table 5.

TABLE 5 PHYSICAL/MECHANICAL PROPERTIES OF INTEGRATED DENTAL PORCELAINSYSTEM machinable ISO Universal Universal Universal block all- PropertyRequirement Opaque dentin/enamel Ingot ceramic Flexural strength 50(PFM/PTM) 162 80 135 115 (MPa) 100 (all-ceramic core) Thermal expansion±0.5 (2x & 12.9 ± 0.4 12.1 ± 0.4 12.0 ± 0.4 12.5 ± 0.4 coefficient4x—applies (as-sintered) (@ 25-480° C.) (as-sintered) @ 25-500° C. toopaque & dentin) 13.1 ± 0.4 13.0 ± 0.4 (ppm/° C.) (simulated pressing)(simulated pressing) Glass transition ±20 540 ± 20 500 ± 20 600 ± 20 575± 20 temperature (° C.) Chemical solubility 100 (dentin & opaque)   17.7  22.6   33.1   40.4 (μg/cm²) 2,000 (ingot & machinable block)

The integrated dental porcelain system of the present invention isdesigned for making PFM, PTM, and all-ceramic restorations in asimplified manner. As described above, the system includes three majoruniversal components: opaque coating, dentin/enamel porcelain, andpressable ingots that can be used interchangeably. For example, the samepressing temperature and same ingot can be used to press either thedentin body when making a PTM restoration and/or all-ceramic core.Furthermore, the same firing temperature and the same opaque coating canbe used to overlay metal substructures for making PFM and/or PTMrestorations. And, the same firing temperature and same dentin/enamelporcelain can be used to veneer over an opaqued metal substructure formaking PFM restorations and/or it can be used to veneer over eitherpressed and/or machined all-ceramic cores for making all-ceramicrestorations.

It should be understood that while the present invention has beendescribed in considerable detail with respect to certain specificembodiments thereof, it should not be considered limited to suchembodiments but may be used in other ways without departing from thespirit of the invention and scope of the appended claims.

1. An opaque composition for coating a metal substructure of a dentalprosthesis, the opaque composition comprising the following components:Components Concentration Range (Wt. %) SiO₂ 42-46%  Al₂O₃ 8-12%  Na₂O2-5% K₂O 6-9% Li₂O 0-2% CaO 0-2% MgO 0-2% ZrO₂ 20-30%  SnO₂ 1-4% Tb₄O₇0-2% CeO₂ 0-3% TiO₂ 0-2% Sb₂O₃ 0-0.1%  Fluorescing agent 0-5%

wherein the composition, after firing to a temperature in the range ofabout 860° to about 900° C., forms an opaque coating over the metalsubstructure, the opaque coating being thermally compatible andthermally stable with a porcelain veneer layer that is later appliedover the opaque coating.
 2. The opaque composition of claim 1, whereinthe composition is in powder or paste form prior to being fired.
 3. Theopaque composition of claim 1, wherein the composition is applied to themetal substructure by spraying, slurry dipping, or electro-depositing.4. The opaque composition of claim 1, wherein the later appliedporcelain veneer layer is applied by a hot pressing technique or handbuild-up technique.
 5. The opaque composition of claim 1, wherein thecomposition, after firing to a temperature in the range of about 800° toabout 1000° C., has flexural strength of greater than 100 MPa.
 6. Aningot porcelain composition for making a dental prosthesis using ahot-pressing technique, the prosthesis having an opaqued metalsubstructure or all-ceramic core, and the porcelain compositioncomprising the following components: Oxide Concentration Range (Wt. %)SiO₂ 63-66%  Al₂O₃ 10-14%  Na₂O 3-7% K₂O 9-12%  Li₂O 0-2% CaO 1-4% BaO0-3% Tb₄O₇ 0-2% CeO₂ 0-2%

wherein the composition, after pressing at a temperature in the range ofabout 870° C. to about 910° C., forms a dentin body layer, the layerbeing thermally compatible with the opaqued metal substructure and aporcelain veneer layer that is later applied over the body layer
 7. Theporcelain composition of claim 6, wherein the composition, afterpressing at a temperature in the range of about 870° C. to about 910°C., has flexural strength of greater than 100 MPa.
 8. The porcelaincomposition of claim 6, wherein the later applied porcelain enamelveneer layer is applied by a hand build-up technique.
 9. The porcelaincomposition of claim 6, wherein a shade stain composition and a glazecomposition are applied over the pressed dentin body layer to form anoverlayer, the shade stain and the glaze compositions, each comprisingthe following components: Oxide Concentration Range (Wt. %) SiO₂ 56-64% Al₂O₃ 6-13%  Na₂O 7-15%  K₂O 7-15%  Li₂O 0-5% CaO 0-3% MgO 2-5% SnO₂0-4% Tb₄O₇ 0-3% CeO₂ 0-2% B₂O₃ 0-5% Sb₂O₃ 0-0.5%  F 0-2.5%  TiO₂ 0-1%

wherein the compositions, after firing to a temperature in the range ofabout 780° to about 840° C., form a shade stain and glaze overlayer overthe pressed dentin body layer, the shade stain and glaze overlayer beingthermally compatible and thermally stable with the pressed dentin bodylayer.
 10. A veneering porcelain composition for making a dentalprosthesis having an opaqued metal substructure, the porcelaincomposition comprising the following components: Oxide ConcentrationRange (Wt. %) SiO₂ 62-65%  Al₂O₃ 8-11%  Na₂O 8-11%  K₂O 4-7% Li₂O 0-2%CaO 2-5% BaO 0-3% MgO 1-4% SnO₂ 0-2% Tb₄O₇ 0-2% CeO₂ 0-2% Sb₂O₃ 0-2%P₂O₅ 0-0.1%  TiO₂ 0-0.1%  F 0-1%

wherein the opaqued metal substructure has not been coated with aporcelain dentin body layer, so that the veneering porcelain, afterfiring at a temperature in the range of about 810° C. to about 860° C.,forms a dentin-enamel layer over the opaqued metal substructure, thedentin-enamel layer being thermally compatible with the opaqued metalsubstructure.
 11. The veneering porcelain composition of claim 10,wherein a glaze composition is applied over the fired dentin-enamellayer to form an overlayer, the glaze composition comprising thefollowing components: Oxide Concentration Range (Wt. %) SiO₂ 56-64% Al₂O₃ 6-13%  Na₂O 7-15%  K₂O 7-15%  Li₂O 0-5% CaO 0-3% MgO 2-5% SnO₂0-4% Tb₄O₇ 0-3% CeO₂ 0-2% B₂O₃ 0-4%

wherein the composition, after firing to a temperature in the range ofabout 780° to about 840° C., forms a glaze overlayer over the fireddentin-enamel layer, the glaze overlayer being thermally compatible withthe dentin-enamel layer.
 12. The veneering porcelain composition ofclaim 10, wherein the composition, after firing at a temperature in therange of about 810° C. to about 860° C., has flexural strength ofgreater than 80 MPa.
 13. A veneering porcelain composition for making adental prosthesis having an opaqued metal substructure, the porcelaincomposition comprising the following components: Oxide ConcentrationRange (Wt. %) SiO₂ 62-65%  Al₂O₃ 8-11%  Na₂O 8-11%  K₂O 4-7% Li₂O 0-2%CaO 2-5% BaO 0-3% MgO 1-4% SnO₂ 0-2% Tb₄O₇ 0-2% CeO₂ 0-2% Sb₂O₃ 0-2%P₂O₅ 0-0.1%  TiO₂ 0-0.1%  F 0-1%

wherein the opaqued metal substructure has been coated with a porcelaindentin body layer, so that the veneering porcelain, after firing at atemperature in the range of about 810° C. to about 860° C., forms anenamel layer over the dentin body layer, the enamel layer beingthermally compatible with the opaqued metal substructure and the dentinbody layer.
 14. The veneering porcelain composition of claim 13, whereina glaze composition is applied over the fired enamel layer to form anoverlayer, the glaze composition comprising the following components:Oxide Concentration Range (Wt. %) SiO₂ 56-64%  Al₂O₃ 6-13%  Na₂O 7-15% K₂O 7-15%  Li₂O 0-5% CaO 0-3% MgO 2-5% SnO₂ 0-4% Tb₄O₇ 0-3% CeO₂ 0-2%B₂O₃ 0-4%

wherein the composition, after firing to a temperature in the range ofabout 780° to about 840° C., forms a glaze overlayer over the presseddentin body layer, the glaze overlayer being thermally compatible withthe dentin body layer.
 15. A veneering porcelain composition for makinga dental prosthesis having an all-ceramic core, the porcelaincomposition comprising the following components: Oxide ConcentrationRange (Wt. %) SiO₂ 62-65%  Al₂O₃ 8-11%  Na₂O 8-11%  K₂O 4-7% Li₂O 0-2%CaO 2-5% BaO 0-3% MgO 1-4% SnO₂ 0-2% Tb₄O₇ 0-2% CeO₂ 0-2% Sb₂O₃ 0-2%P₂O₅ 0-0.1%  TiO₂ 0-0.1% 

wherein the all-ceramic core contains a porcelain dentin body layer, sothat the veneering porcelain, after firing at a temperature in the rangeof about 810° C. to about 860° C., forms an enamel layer over the dentinbody layer, the enamel layer being thermally compatible with theall-ceramic core.
 16. The veneering porcelain composition of claim 15,wherein a glaze composition is applied over the fired enamel layer toform an overlayer, the glaze composition comprising the followingcomponents: Oxide Concentration Range (Wt. %) SiO₂ 56-64%  Al₂O₃ 6-13% Na₂O 7-15%  K₂O 7-15%  Li₂O 0-5% CaO 0-3% MgO 2-5% SnO₂ 0-4% Tb₄O₇ 0-3%CeO₂ 0-2% B₂O₃ 0-4%

wherein the composition, after firing to a temperature in the range ofabout 780° to about 840° C., forms a glaze overlayer over the dentinbody laer, the glaze overlayer being thermally compatible with thedentin body layer.